On 2006-10-17 09:04:35 +0100, Adrian said:

HI Andy

On Mon, 16 Oct 2006 23:00:15 +0100, Andy Hall
wrote:

On 2006-10-16 20:46:59 +0100, Adrian said:



I did take a look in the loft, and the joints between the dish coax
and the downlead in the walls are simply 'wrapped & insulating tape' -
maybe there's a cock-up there ??
\

Ah.... They've used cable that was in the wall?

Yup !

The electrician (bless him) did go to the trouble of installing a
double aerial socket and a single side-by-side - so he was (maybe ?)
thinking 'Sky+ and terrestrial'.
I looked at the 'built-in' cable last night and couldn't see any info
printed on it - it's got braid and foil screening, and is
semi-airspaced (the white plastic 'honeycombe' effect) - but I
couldn't see any maker's mark....

If there's foil it might be CT 100 but no guarantee.

I would arrange for the whole thing to be done in known CT100 all the
way then you know what you have.



There is a pretty good chance that this is TV coax. This cable is
basically ****e and is marginal for UHF TV which has a frequency range
up to about 900MHz. The frequencies used between LNBs and receivers
go to around twice that and the effect will be signal loss and possibly
cable reflections etc.

Hmmm !

I did double-check the signa; strengths etc on the skybox - last night
both 'meters' were showing 50% strength, input 1 showed about 40%
quality and 2 showed about 30%. Swapping the leads at the wall plate
made not difference, also swapping the leads at the bcak of the skybox
had no effect.... dunno what that proves ?? g

That they are equal.



The LNB cable should be CT100 and it should be home run all the way to
the receiver.


That'd be ideal, I agree...

Must try to get up there and measure the size of the dish.... that
might prove something.....?

Probably that it;s too small.

You would need to ask a known good local installer, but I would expect
that a 90-100cm round dish with good LNB and CT100 cables all the way
to the receiver would be the expectation.





Thanks
Adrian